Boiler



March Z 1926.

L. P. MICHAEL Filed Feb. 23

1922 4 Sheets-Sheet '1 LL P. MHCHAEL BOILER Filed Feb. 23 1923 4 Sheets-Sheet 2 March 2 9 1926.

L. P. MICHAEL BOILEH Filed F'eb. 23, 1923 4 Sheets-Sheet 3 March 2 1926. 1,575,375

L. P. MICHAELl BOILER Filed Feb. 23, 1923 4 Sheets-Sheet 4 6' LGREN IP. MICHAEL, OF ELMHURST, ILNOIS, ASSIGNR OF 01'? ;tal-HALE T,

BENTEY, OF AEK EARK, II'INDIS.

,Application filed February 23, 1923. Serial No. 620,553).

7 10 aZZ witam t may concern:

Be it known that i, Lonnn P. MICHAEL, a citizen of the United States., residing at Elmhurst. in the county of Du Page and State of Illinois, have invented certain new and useful lmprovements in Boilers, of which the following; is a specification.

This invention rclates to iinprovements 1n boilers, and has reference more particularly to boilcrs of the water tube' 'typen The invention has been designed more especially with reference to its adaptation to, and use as, a locomotivc boiler; but its novel structural principles are also equally adaptable to water tube boilers of the marine and stationary types; 'and although I have herein shown and described a particular embodi'- ment of the invention adaptable to locomotive practice, it should be undcrstood that, in its broad aspects, the invention is by no means limited to locomotive boilers but also comprehends boilers of all other kinds and for all other purposes wherein steam is generated from water circulating through tubes bathed in products of combustion from the fire box and also subject to the ra'diant heat of the fire.

Among' the salient objects of the invention are, to rovide an improved Water tube boiler of -very compact l construction and relatively light Weight, especially as compared with the standard locomotive type construction; to provide an improved Water tube boiler thatfwill have a much higher efliciency and will'evaporate a much larger quantity of water per square foot of heating surface than the present locomotive or fire box type of boiler; to provide an improved water tube boiler of such a construction that it will have a comparatively small-external radiating surface, and Will efl'ect a very lrapid'circulation of the entire volume of water in the boiler when in service. Other objects are to provide a construction rea'dily permitting of repair-s and renewal of parts, and especially the removal and replacement of the water tubes without the necessity of removingI other tubes than those .required to be removed and replaced; to provide an improved construction permitting the use of the maximum number of water tubes Within the space limits of the boiler; to provide a construction of Water tube boiler wherein the arrangement of tubes shall be such as tov aford a strong, well braced, and rigid construction; and to provide a construction of water tube boiler well adap'ted to the application of superheating apparatus.

Other objects and attendant advantages of the invention will be apparent 'to persons 530 skilled in the art as the same becomes better' understood by reference to the following detailed description, taken in connection with the acconipanyin'g drawings, wherein I have illustrated one practical and ap- 35 proved mechanical form of the invention as cmbodi-ed in a'boiler more especially de signcd for locomotive practice, vand in which- Fig. 1 is a Vertical longitudinal section of niy improved boiler taken on 'the line 1-1 of Fig. 2;

Fig. 2 is a vertical cross section taken on the line 2-2 of Fig'. 1;

Fig. 3 is a. Vertical cross section taken the line 3 -3 of Fig 1 just inside the front wall of the boiler casing and showing the arvrangememt of tubes at the front end of the boiler;

Fig. 4 is a horizontal section on. the line 30 wall and 8 the rear wall of a generally rec- 'W tangular boiler shell or housing; these Walls being provided with internal linings of suitable fire resist'ing insulating` material such as sheets or plates of asbestos designated by 5', 6', 7' and 8', respectively.

Located within and extending lengthwise of the corner regions of the boiler housing are four' circular drums. The two lower drums, designated by 9 and 9', may be mounted in cradles 10, 10', or other suitable supports, on and between the inner edges of which extencls a coal-burning graf/e conventionally shown at 11. 12 and 12' designate the corresponding steam and Water` drums mountcd in the upper corner regions of the housing.

Inner battle walls or plates 13, 13' of high temperature cement or other suitable material extend from the lower drums 9, 9', up-

wardly substantially parallel With the sides no of the boiler housing, curving thence in- Wardly toward each other and terminating preferably at or slightly above the horizontal plane of the axes of the upper drums 12, 12', as clearly shown in Fig. 2. Outer baflle walls or plates 14, 14' extend downwardly from the. drums 12, 12', terminating a slight distance above the lower drums 9, 9'.

Connecting the lower and upper drums 9 and 12, and disposed between the adjacent sidewall of the boiler housing and the baflle 14 are a plurality of rows, herein shown as three, of tubes 15, extending the full length of the boiler; these tubes constituting downflow tubes for water not evaporated in the steam and water drum 12 from the latter to the water drum 9. An identical series of 'tubes 15' eonnects the drums 9' and 12' on and thence obliquely across the upper portion of the boiler above the fire-box into the steam and water drum 12' on the other side; the tubes of three of the rows being shown as starting from points in the drum 9 behind the baflle 13, and extending through the latter and the opposite baffle'l-', and the tubes of the innermost row being shown as starting from points in front of the bafile 13 andv extending through the companion baflle 13'. Similar and oppositely inclined rows of tubes 16' connect the lower water drum 9' with the upper steam and water drum 12. To permit the upper inclined portions of the two series of tubes 1-6 and 16' to cross each other in the upper region of the boiler, one tube of each adjacent pair in each longitudinal row is bent over into the Vertical plane of its Companion tube substantially at the points where the Vertical and inclined portions of the tubes merge. This structural feature is of great importance, because permitting the use of praetieally twice as many upfio'w water tubes as would otherwise be possible with a given length of boiler housing in an arrangement where the tubes cross each other as shown, while still leaving ample passage space between the tubes 'for the gases of combustion.

The intersecting rows of tubes 16 and 16' do not, in the preferred construction, extend quite the full length of the boiler; but preferably terminate slightly short ofv the end walls of the boiler to permit the introduction of, additional or auxiliary water heating tubes throughout the end areas of the fire box 01' combustion Chamber. The preferred arrangement at the rear end is illustrated in Figs. 5 and 6, wherein it will be seen that the rear end portionsof the drums 9 and 12 and 9' and 12' are connected by groups of tubes 17 and 17', respectively.V The tubes of each group are increasingly 'box or combustion Chamber.

offset laterally toward the transverse center of the end wall of the boiler throughouttheir intermediate portions, each group oceupying substantially half the end wall area. Throughout the greater part of their length these tubes lie in two Vertical planes, the tubes intone plane beingstaggered in relation to the tubes of the other plane, and a certain of these tubes are Offset laterally and inwardly where they enter the drums, as shown in Fig. 6. This structural detail, however, is optional; the important feature being the arrangement of upflow tubes 17, 17' in the end region of the boiler so disposed asV to form a water tube end wall of the fire box or combustion chamber, completely covering and protecting the adjacent end wall of the housing.

Figs. 3 and 4 illustrate the water tube arrangement at the front of the boiler which forms a water tube front wall for the fire The location and arrangement of the tubes 18 and 18' are lsimilar to those of the tubes 17, 17'; but the tubes of the two groups are locally bentl or offset thronghout approximately a semi-oval slightly above their lower ends, aslshown at 18 and 18b in F ig. 3 thereby forming between them a generally oval opening or space 19 which, as shown in lFig. 1, rcgisters with the opening 20 in the front wall of the boiler housing, through bends in these eurved tubes are avoided in order to facilitate Vthe passage of cleaners through them.

The structure as thus far described is complete for boilers where superheating of the steam is not required. The products of combustion rise between the inner battles 13 and 13', flowing around the inner rows of water tubes 16 and 16' and the intcrsectin'g portions of all the rows 16 and 16' of water tubes; flowing thence over the upper edges of the baffles 13, 18' downwardly between the upper drums and the baflles, again fiowing around'the rportions of the tubes 16 and 16|' that lie outside the baflles 13,' 13' thence'around the lower edges of the baffles 1.4, 14'` and upwardly between the baflles 14 and'14' and the side walls of the boiler.

h-ousing, flowing around the water downflow tubes 15` 15', by which circulation the greatest possible amount. of heat is absorbed by the water in the tubes. From the spaces between the outer sides of the drums 12 and12' and the opposite walls of the boiler housing the products of combustion pass to any suitable point of discharge, such as a chimney or smokestack (not shown). As to the flow of the water, the feed water may be injected either into the upper drulns 12', 12', or into the lower drums 9, 9',\which latter are constantly maintained full of'water. From these latter the water fiows upwardly through the tubes 16, 16' into the drums 12' and 12, respectively, giving off the steam generated during such flow. The water in the drums 12, 12' that is not evaporated into steam flows downwardly through the tubes 15, 15', back into the water drums 9, 9', and thence upwardly through the tubes 16, 16', This takes place throughout the major portion of the boiler, but at the end portions the upflow of water from the drum 9 is direct to the drum 12 through the tubes 17 and 18, and from the drum 9' to the drum 12' through the tubes 17' and 18'. It will thus be seen that the fire chamher is formed with water tube walls on its sides, ends and top, so that a very large heating surface is provided and the heated products of combustion circulating through and fiowing from the fire chamber are most eliciently used to promote the rapid flow of the water through the tubes and a correspondingly rapid generation of steam. The path of the products of combustion is mostly counter-fiow to that of the water, which effects a desirable method of heat exchange. The arching of the tubes in intersecting fashion throughout the top area of the fire chamber also enables the radiant heat of the fuel to be most directly and efficiently applied to the generation of steam. The lower portions of the two lower drums 9, 9' serve as settling chambers for mud and scale which'can be easily blown from thev bottom of each drum by means of blow-off coeks, or washed out through washout plug holes made accessible by application of manholes located in one or both ends of' each lower drum,` said manholes being indicated at'9fl. The two upper drums provide a large steam liberating surface ;when the working water level is maintained near the center line of' the drums. A large steam space is also provided in the upper portion of the top drums over the water. The upper drums are also provided with manholes indicated at 12 to permit access for cleaning the tubes.

The described construction adapts itself well to the application and use of a steam superheater where desired, and in the drawings I have illustrated the application of such a superheater. 21 and 21' designate a pair of cylindrical steam headers located alongside the inner upper portions of the upper steam drums 12 and 12', respectively. 22 designates each of a longitudinal row of steam pipes fitted into 'the upper portion of the drum 12 and continuous with horizontal coils 23 that are located in the top portion of the boiler housing directly over the upper 'ends of the inner baflles 13, 13'. The vlower legs of these coils connect by pipes 24 into the steam header 21'. A'similar row of pipes 22' connected into the upper portion of the drum 12' connect with similar superheater coils 23' that are internested with thecoils 23, the lower limbs of said coils 23' communicating by pipes 24' with the superheater steam header 21. It is manifest that by reason of the location of the superheater coils 28, 23' they are subject to the heating influence of the'products of combustion at nearly the hottest stage of the lat-ter. Of course, the superheater pipes may return to the same side of the boiler from which they start.

TVithn the drums 12 and 12' I have shownlongitudinally extending bafiles 25, 25' underlying the receiving ends of the pipes 22, 22' to deflect particles of water and prevent the latter from passing over with 'the steam into the superheaters.

lVhere it may be desired to equip the boiler with a mechanical stoker. this may be readily accomplished: and in Figs. 1 and 3 I have shown a pair of stoker tubes 26 entered through the front wall of the boiler housing above and onopposite sides of the fire door opening: the tubes 18 and 18' being locally spread apart at points behind the openings for the stoker tubes, as shown at 18 and 18d in Fig. 3 to permit the passage of thestoker tubes between them.

It is believed that the principle of the invention, its novel structural features, and the numerous advantages i'nherent therein will be readily understood by engineers and others familiar with the art of boiler construetion without further detail description. Manifestly, the number, spacing and group-- ing of the tubes Will be more or less varied to suit the sizes and capacities of different boilers, and the details of structure and arrangement may be otherwise considerably vmodified from those herein shown withoutinvolving any departure from the principle of the invention or sacrifioing any of the advantages and utilities thereof. I-Ience, 1 rescrve all such variations and modifications as come within the spirit and purview of tht` appended claims.

I claim- 1. In a boiler of the type described, the combination of a `housing of generally rectangular form,` drurns disposed in and lengthwise of the corner regions of said housing, and one or more longitudinal rows of water tubes connecting each lower drum with the upper drumon the opposite side and unitedly forming the roof of the fire box, the tubes of adjacent pairs in each row llO being bent into a common Vertical plane throughout the roof region to provide increased space for the intersection of said disposed in and lengthwise of the corner regions of said housing, two groups of water tubes connecting the lower and upper drums on each side of the. boiler, respectively, just inwardly of an en-d wall of the latter, the

tubes of each group beingbent inwardly' throughout their intermediate portions to cover substantially one-half of said end wall, and said tlibes throughout their intermediate portions being disposed in front and rear closely adj acent Vertical' transverse rows, with the tubes in one row in staggered relation to the tubes in the other row, and a filling of fire-resisting material between the rear side of each tube of 'the front row and the two adjacent tubes of the rear row lyin` therebehind. i

3. In a boiler of the type described, the combination of a housing of generally rectangular form, drums disposed in and Iengthwise of the corner regions of said liousing, and one or more longitudinal rows of water tubes connecting' the inner 'side -of each lower drum with the inner side of the upper drum on the opposite side of the boiler, said tubes extending vertically for some distance from the lower drums and' thence obliquely to their connections with the upper drums, and the oblique portions of alternate tubes in each row being bent into the Vertical plane of adjacent tubes whereby the space Vacated by the bent tubes on one side accommodates the tubes extending from the oppositei side, thereby leaving between the intersecting tubes a sutficient Space for passage of the gases of combu'stion,

4:. In a water tube boiler, the combination of 'a generally reetangular housing, drums located in and lengthwise of the corner regions of said housing, water upfiow tubcs eonnecting the lower drum on each side with the upper drum on the opposite side, water downfiow tubes connecting the upper and lower drums on each side, baflic plates extending from said lower drums upwardly through said water upfiow tubes to points above the latter and between said upper drums, and steam superheater coils disposed crosswise of 'the upper ends of Said baffle plates and connected into said upper drums.

5. n a Water tube boiler, 'the combination of a generally rectangular housing, drums located 'in and lenqt'hwise of the corner regions of said housing, water upfiow tubcs connecting the lower drum on each side with 'the upper drum on the opposite side, water downfiow tubes connecting the upper and lower drums on each side, baflle plates extending from said lower drums upwardly and inwardly through said water upflow tubes to points above the latter and between said upper drums, steam headers located opposite the inner sides of said upper drums, and lsteam superheater coils disposed crosswise of 'the upper ends of said bafile platcs, each of said superheater coils being connecte-d at one end into one of said upper drums and at its other end into one of said steam headers.

LOREN P. MICHAEL. 

